An electrophoretic display (EPD) is a non-emissive device based on the electrophoresis phenomenon of charged pigment particles suspended in a solvent. The display usually comprises two plates with electrodes placed opposing each other. One of the electrodes is usually transparent. A suspension composed of a colored solvent and charged pigment particles is enclosed between the two plates. When a voltage difference is imposed between the two electrodes, the pigment particles migrate to one side or the other, according to the polarity of the voltage difference. As a result, either the color of the pigment particles or the color of the solvent may be seen at the viewing side. In general, an EPD may be driven by a uni-polar or bi-polar approach.
Most of the driving methods currently available for either uni-polar or bi-polar approach attempt to ensure that the images displayed have little or no residual image of the previous image. However, the driving time is long. In order to shorten the driving time, one can apply driving voltages only to the updated areas and apply no driving voltages to the non-updated areas. However, in practice, the driving voltage (the difference between the voltage applied to the pixel electrode and the voltage applied to the common electrode) is difficult to be kept at zero, which will cause the images to degrade in the non-updated areas.
In addition, currently available waveforms have disadvantages for driving two consecutive images which are similar, for example, the transition from one image to another may have a “flashing” appearance and also slow, or when non-flashing waveforms are used, the areas not intended to be changed are difficult to remain un-changed.
Relative to driving hardware, the currently available methods require separate circuits for the common electrode and the pixel electrodes.